Singulator conveyor

[0001] The disclosure relates generally to conveyors and more particularly to a singulator conveyor.

[0002] It is known to employ a singulator conveyor to unscramble randomly oriented articles. Examples of such traditional singulator conveyors can be found in U.S. Pat. No. 5,769,204 entitled “Singulator Conveyor System Having Package-Return Conveyors” which issued to Okada and Ydoate on Jun. 23, 1998, and U.S. Pat. No. 5,400,896 entitled “Unscrambling Conveyor” which issued to Loomer on Mar. 28, 1995. Both of these patents are incorporated by reference herein.

[0003] Another traditional singulator conveyor is known as the Accord™ singulator from the present assignee. This singulator employs a central conveyor belt outwardly bordered by sets of driven rollers which are only skewed in a top view direction. These Accord™ singulator rollers are horizontally coplanar with each other and are vertically higher than the central conveyor belt. While this Accord™ singulator is a considerable improvement in the industry, it still allows envelopes and packages to restack upon each other as they move from the rollers to the central conveyor belt.

[0004] Furthermore, U.S. Pat. No. 2,566,417 entitled “Conveyor Switch” which issued to Holm on Sep. 4, 1951 discloses a switching mechanism between two conveyor branches. This conveyor switch is entirely unrelated to a singulator conveyor, however, it does employ downwardly and rearwardly angled diverging outboard rollers. Nevertheless, it is noteworthy that this prior device has laterally pivotal idler rollers which are passive.

[0005] In accordance with the present invention, a conveyor machine is provided. In another aspect, a singulator conveyor employs three-dimensionally obliquely skewed driven rollers angularly offset from a primary feeding and downstream direction, outboard of an adjacent driven conveyor having a top surface moving in the primary feeding and downstream direction. A further aspect provides a downstream moving conveyor belt or rollers which are vertically higher than the adjacent outboard skewed and converging driven rollers. A method of using an unstacking singulator for parcels is also disclosed.

[0006] The present singulator conveyor is advantageous over conventional systems. For example, the present conveyor directs parcels in an upwardly angled and converging manner to tip onto the adjacent conveyor while also deterring stacking of side-by-side parcels, such as packages and especially envelopes. The present singulator conveyor significantly improves singulating throughput efficiencies, thereby lessening the recirculation burden traditionally observed, while additionally deterring problems with downstream automated handling and electronic reading of bar code addresses on the parcels due to traditional stacking concerns which otherwise obscure the lower of the stacked parcels. Additional advantages and features of the present invention will be ascertained by the following description and appended claims, taken in conjunction with the accompanying drawings.

[0020] A preferred embodiment of a conveyor machine 21 is shown in FIGS. 1-3. Conveyor machine 21 includes a feeding conveyor station 23, a singulator conveyor station 25, an eliminator conveyor station 27, recirculating conveyor stations 29, an outlet conveyor station 31, an adjustable speed feedback metering conveyor station 33, and a sorting and automated address reading station. Multiple parcels, such as mailing boxes 35 and generally flat envelopes 37 capable of holding 8% by 11 inch letters, are placed onto feeding station 23 in a somewhat haphazard manner such as by dumping a container or bag of the parcels thereupon. Feeding conveyor station 23 further includes an inclined conveyor section 43 which raises and then drops the parcels onto singulator station 25. Furthermore, multiple legs 39 and protective fences 41 are provided along the sides of conveyor machine 21.

[0021] Reference should now be made to FIGS. 3-9 which illustrate greater details of singulator 25. Singulator 25 has a central conveying section 51, preferably a longitudinally elongated and continuous conveyor belt 51, with an upper surface 53 for frictionally contacting against an underside of parcels 35 and 37. Conveyor belt 51 is wrapped around at least fore and aft pulleys 55, which rotate about rotational axes which are horizontal and perpendicular to a primary and longitudinal feeding direction 61. Conveyor 51 carries and conveys the parcels located thereon in feeding direction 61. Conveyor belt 51 is driven by an electric motor 63 and driving pulley mounted to a bottom side of singulator 25.

[0022] A mirrored image pair of driven and converging sets of rollers 65 are located laterally outboard of central conveyor belt 51. Each of these rollers 65 is preferably circular-cylindrical, metallic and rotates about its central axis 67. Inboard ends 69 and outboard ends 71 of rollers 65 are journalled by stationary brackets 73 and bearings such that each roller 65 is generally laterally elongated between ends 69 and 71, with the exception of a few shortened leading or trailing rollers 75. Some of rollers 65 include an elastermeric O-ring 77 adjacent a middle thereof. An electric motor 81, output pulleys 83 and continuous belts 85 frictionally drive bottoms of each set of rollers 65 such that upper surfaces 87 of rollers 65 rotate in a generally downstream and converging direction 89 essentially toward conveyor belt 51.

[0023] As can best be observed in FIGS. 4-6, 8 and 9, upper surface 87 and rotational axis 67 of each singulator roller 65 are three-dimensionally skewed and obliquely angled with its outboard end 71 oriented downstream (when viewed from the top as in FIGS. 4 and 6) and lower (as viewed from the side and end as in FIGS. 8 and 9) relative to inboard end 69. Thus, each singulator roller 65 is upwardly angled toward centerline feeding direction 61 by 8-20° off of horizontal, and more preferably 8-10°, at angle α; the steeper angles may be employed if high friction rollers are used. Furthermore, top view skew angle β of each upper roller surface 87 and axis 67 are 15-40° and more preferably about 20° relative to primary feeding direction 61. The specific three-dimensionally skewed angles advantageously cause convergence of parcels from driven rollers 65 onto central conveyor belt 51 while also deterring parcel stacking.

[0024] It is noteworthy that upper surface 53 of conveyor belt 51 is vertically located 1-2 mm higher at d above the highest point of rollers 65. Nevertheless, a projection line 91 from upper surface 87 of each roller 65 also projects a distance d of about 1-2 mm above the adjacent corner of conveyor belt 51. The raised nature of conveyor belt 51 and the three-dimensionally skewed orientation of singulator roller 65 deter stacking of the parcels, especially laterally adjacent envelopes 37, since the abutting parcel edges act as thicker packages abutting into each other through an edge contacting a bottom, rather than a traditional coplanar arrangement which causes the parcels to slip above or below each other. Moreover, the present construction causes the parcels to inwardly and upwardly move until a tipping point is reached with regard to the parcel's center of gravity. Thereafter, the center of gravity of each parcel 35 and 37 is controlled by central conveyor belt 51 and is no longer driven by roller 65. It is also noteworthy that the lateral width w of conveyor belt 51 is at least 100 mm, and more preferably at least half the typical parcel width, yet less than a lateral direction of elongation W of each adjacent nominal roller 65 (as differentiated from the few shortened leading or trailing rollers 75).

[0025] Reference should be made to an alternate embodiment singulator 125 of FIG. 10. In this variation, a single upward set of driven and converging rollers 165 is employed adjacent a single driven and higher conveyor belt 151. This conveyor belt 151 is laterally wider than the prior version. Moreover, an upper parcel contacting surface 187 and rotational axis 167 of each driven roller are three-dimensionally skewed relative to a centerline and primary feeding direction as with the prior embodiment.

[0026] FIG. 11 illustrates yet another variation of singulator 225. In this construction, a pair of laterally outboard and three-dimensionally skewed driven rollers 265 are provided like that of the first embodiment. However, a central conveyor employs a set of driven rollers 251 each having a rotational axis 295 oriented perpendicular to the primary downstream feeding direction. Parcel-contacting upper surfaces 253 of central conveying rollers 251 are raised above the outboard converging singulator rollers 265. Rollers 265 and 251 are each circular-cylindrical and laterally elongated by at least 25 mm and more preferably at least 100 mm.

[0027] Eliminator station 27 includes a central conveyor belt 301, or alternately driven rollers, which are centered between outboard sets of diverging angled rollers 303. Outboard diverging rollers 303 are driven by electric motor and underlying frictional belt mechanisms. Outboard rollers 303 are horizontally coplanar with each other, although they can be three-dimensionally skewed. In other words, the rotational axis and upper surface of each diverging roller of eliminator 27 are obliquely angled relative to downstream feeding direction 61 in only a top view but not otherwise skewed or angled in an end or side view. Additionally, a set of chutes 305 or walls are stationarily angled to direct side-by-side packages remaining on rollers 303 away from conveyor belt 301 and onto recirculation belts 29. An exemplary eliminator station is disclosed in U.S. Pat. No. 5,701,989 entitled “Conveyor for Removing an Article Conveyed Abreast of Another Article” which issued to Boone et al. on Dec. 30, 1997, and is incorporated by reference herein.

[0028] Another alternate embodiment singulator 325 is shown in FIGS. 12 and 13. This variation includes laterally individualized and converging sets of roller wheels 365 on either outboard side of a central conveyor belt 351. Roller wheels 365 are driven by electric motors and conveyor belt 351 is also driven by an electric motor. Each roller wheel 365 is three-dimensionally skewed with their axes obliquely offset angle β relative to central feeding direction 361 in a top view, and offset angle α downwardly toward their outboard grouped ends relative to a horizontal plane set by a parcel-contacting upper surface of belt 351. The coaxial axes of each lateral group of roller wheels 365 are stationarily set by their upstanding brackets.

[0029] While various embodiments have been disclosed, it should be appreciated that other variations may be made. For example, a tapered driven roller may be employed although many of the present advantages will not be realized. Furthermore, at least 15, and more preferably at least 30, driven singulator rollers can be used on each side of a central conveyor belt, however, a greater or smaller quantity may be employed although certain advantages may not be achieved. The roller and belt-driving actuators and transmissions may alternately be varied to use pneumatic motors, sprocket and chain transmissions, cables, gears and drive shafts, and many other mechanisms, although certain advantages may not be realized. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. It is intended by the following claims to cover these and any other departures from the disclosed embodiments which fall within the true spirit of this invention.